No5s were evidently issued to 1st and 6th Airborne Division in March or April 1945. Units of these divisions were used to occupy Hamburg & Denmarkin the period 27 April to 7 May (when Germany
surrendered), and then Norway
from 8 May onwards. Photos exist of these units carrying No5s during these operations.
I've seen several rifles that were FTR'd within a year of manufacture - one No4 was FTR'd within 3 months of its build date! There are probably all sorts of reasons why such rifles had to be fixed: could be damage or wear during intense training use, particularly if the rifle was a "pool" weapon in constant use in a training depot, or perhaps the discovery of a manufacturing defect of some kind for which there were no spares yet in the system.